Method of and apparatus for feeding and applying insulating disks to conductors



' A. c. FRANKWICH METHOD OF AND APPARATUS FOR FEEDING AND Dec. 25, 19512,579,487

' APPLYING INSULATING DISKS TO CONDUCTORS 2 Sl-IEETS-Sl-EET 1 Filed Oct.10, 1946- INVENTOR AC. FRAN/(W/CH ATTORNEY Dec. 25, 1951 Filed 001;. 10,1946 A. C. FRANKWICH METHOD OF AND APPARATUS FOR FEEDING AND APPLYINGINSULATING DISKS TO CONDUCTORS 2 SHEETSSHEET 2 1J0 I V 30 FIG. 2

wvmrok A. c. FRANKW/CH ATTORNEY Patented Dec. 25, 1951 METHOD OF ANDAPPARATUS FOR FEEDING AND APPLYING INSULATING .DISKS 'IO CONDUCTQRSAlexander (J. Frankwich, Baltimore, Md., assignor to Western ElectricCompany, Incorporated, New York, N. Y., a corporation of New YorkApplication October 10, 1946, Serial No. 702,494

8 Claims. (o1..29 155.5)'

This invention relates to methods of and apparatus for feeding andapplying insulating discs to conductors, and more particularly tomethods of and apparatus for expanding slits in plastic insulating discsto facilitate application of the discs to conductors.

In some types of apparatus for forming coaxial cable core units of atype having washerlike, plastic insulating discs positioned on a centralconductor, the insulating discs are slit radiallyand are wiped onto aconductor, the conductor passing through the slits into the centralopenings in the discs. In the past, in order for the conductor to passthrough the slits, the slits have been expanded by a wedging action ofthe conductor thereon as the slits are wiped thereover. When the slitsin the discs are expanded by the conductor, they are expanded abruptly,and as aresult, the discsare sometimes damaged physically. Furthermore,if the conductor has loose particles of conductive material on thesurface thereof, the walls of the slits in the insulating discssometimes carry away the conductive particles as they are wiped onto theconductor. The conductive particles reduce the dielectric strength ofthe insulating discs along the slits thereof, and sometimes causedielectric breakdowns in the discs. The dielectric strength of the discsapplied to the conductor is tested, and if any of the discs aredefective, the entire cable forming apparatus must be stopped in orderto replace the defective discs with nondefective discs. 7

1 An object of the invention is to provide new and improved methods ofand apparatus for feed ing and applying insulating discs to conductors.

-A further object of the invention is to provide new and improvedmethods of and apparatus for expanding slits in plastic insulating discsso that, when the discs are wiped onto a conductor, at least the majorportions of the walls of the slits are held out of contact with theconductor and pressure on the discs by the conductor and contaminationof the walls of the slits in the discs by foreign particles on theconductor are minimized.

In a method illustrative of the invention, a washer-like, plasticinsulating disc having a radial slit therein extending from the outerperiphery thereof to the central aperture thereof is moved through apredetermined path to a conductor. As the disc approaches the conductor,the slit is expanded, and the disc is moved onto the conductor. 7 .Theexpansion of the slit is sufficiently gradual that. the. disc-is notmechanically damaged thereby. The width of the expanded slit is suchthat for the most part, the walls of the slit do not contact theconductor as the disc is moved onto the conductor.

An apparatus illustrative of the invention inciudes an applicator wheelhaving a plurality of notches therein for carrying washer-likeinsulating discs and for applying the insulating discs to a conductor. Aknife slits the discs carried by the applicator Wheel so that the. discsmay be wiped onto the conductor and an expander positioned near thepoint of application of the discs to the conductor serves to expand'thediscs as the discs are wiped onto the conductor by the applicator wheel.The expander opens the slits in the discs in such manner that the discsare not crushed and opens the slits sufiiciently to insure that themajor portions of the walls of the slits do notcontact the conductor asthe discs are wipedcnto the conductor, whereby contamination of thewalls of the slits is avoided.

Fig. 1, and I r Fig. 5 is an enlarged, fragmentary, substantiallyvertical section taken along line 5-5 of Fig. 1.

Referring now in detail to the-drawings, there is shown in Fig.1 anapparatus for feeding, slitting and applying washer-like, plasticinsulating discs it-lll composed of a dielectric material, such as, forexample polyethylene, to a conductor H to form a core unit of a coaxialcable. The complete apparatus is described and claimed in copendingapplication, Serial No. 702,491, filed October 10, 1946 byv S. E.Brillhart. .The discs Ill-l0 are fed to straight, vertical guide chutesl2 and I3 by a hopper feed I5 certain features of which are describedand claimed in my copending application, Serial No. 702,493, filedOctober 10,1946. The guide chutes I2 and i3 feed the. discs by gravityto transfer devices it and I1,

respectively. which feed the discs into notches 2020 and 2|2| formed ininrunning applicator wheels 22 and 28, respectively. The applicatorwheels 22 and 23 move the discs over knives 26 and 21, respectively,which form line-like radial slits 28-28 in the discs.

The applicator wheels 22 and 23 move the discs Ill-I along thin arcuateguides 30 and 3|, respectively, extending from the knives 26 and 21,respectively, and along expanders 32 and 33, re-

spectively, and apply the discs to the conductor II, which enters theholes in the discs through the slits 28-28 formed therein. The thinarouate guides 30 and 3| form continuations of the knives 26 and 21 andenter the slits 28-28 immediately after they are formed. The guides holdthe discs Ill-Ill slightly open and in oriented positions as the discs.are moved by the ap licator wheels 20 and 2| toward the conductor II, inwhich positions the slits are directed radially with respect to theapplicator wheels.

The wedge-shaped expanders 32 and 33 are identical, and for purposes ofsimplicity, only the expander 32 will be described in detail. One end 40(Fig. 3) of the expander 32 is the same thickness as and abuts an end ofthe arcuate guide 30 so that the expander engages the walls of the slits28-28 as the discs are moved therealong. The expander 32 graduallyincreases in thickness to the opposite end 4| thereof.

As the discs Ill-l0 are moved along the expander 32, the expander 32gradually opens the slits 28-48 therein, and as outside corners 4545(Fig. 5) .of the slits start to pass over the conductor ll, thesecorners are held suiiiciently far apart to insure that they do notcontact the conductor I. As the discs are moved further along theexpander 32, the slits 2B28 are expanded still more in order that mostof the surfaces of walls 46-46 of the slits will not contact theconductor and cannot be contaminated thereby. When the discs are almoston the conductor, they are moved off the end 4| (Fig. 3) of the expander32 and the portions of the walls 46-46 of the slits near inside corners4'|4| of the slits contact the conductor. At this point, the slits areopened almost sufiiciently for the corners 414'| to move over theconductor and hold the outer portions of the walls 4646 out of contactwith the conductor. The applicator wheel 22 then wipes the insidecorners 41- 41 of the slits overcenter on the conductor and the discssnap into place thereon.

The expanders 32 and 33 are mounted on a conductor guide 50, and guidethe conductor H therebetween. The applicator wheels 22 and 23 supportthe conductor passing therebetween as the discs |0|0 are applied to theconductor alternately by the wheels.

In the method and apparatus described hereinabove, the discs ||l--l0 aremoved along the long. thin guides 30 and 3| which keep the discsoriented but keep the slits 28--28 in the discs only slightly open sothat no permanent deformation of the discs occurs from the travel of thediscs along the long guides 30 and 3|. The discs then are moved over therelatively short expanders 32 and 33 which are sufliciently long to openthe slits gradually enough to prevent crushing the discs, but which areshort enough that no permanent deformation of the discs is caused bythe'expanders.

The expanders 32 and 33 expand the slits relatively slowly andsufiiciently to cause the conductor I to expand the slits only a smallamount further as the final stages of the application of the discs tothe conductor are effected. Hence,

the discs are not bent or crushed as they might be if they were forcedover the conductor without preexpansion of the slits therein. Also, ifthe conductor has any loose conductive particles on the peripherythereof, the particles are not pressed against the walls 46-46 of theslits 28-28 to form conductive paths, except for theportions of thewalls adjacent to the inside corners 4'|4| of the slits. Hence,contamination which might cause dielectric breakdown of the discs isminimized.

The above-describedmethod and apparatus are particularly advantageous infeeding and applying discs composed of polyethylene to conductors. Suchdiscs, while sufficiently hard to have the necessary mechanicalproperties if placed on the conductor undamaged, are soft enough thatthey were sometimes damaged as they were placed on conductors byordinary methods and apparatus. In the method and apparatus describedhereinabove, the discs are placedon the conductor without permanentlydeforming the discs and without crushing the discs. Hence, the discsadhere firmly to the conductor, and do not slide along the conductorafter they have been applied thereto.

What is claimed is:

1. The method of feeding and applying insulating discs to conductors,which comprises moving through a predetermined path to and onto aconductor a washer-like insulating disc having an inner periphery, anouter periphery and an opening extending from the outer peripherythereof to the inner periphery thereof, and gradually expanding theopening as the disc approaches the conductor and is moved onto theconductor to prevent abrupt expansion of the opening as the disc ismoved onto the conductor.

2. The method of feeding and applying insulating discs to conductors,which comprises moving a discontinuous annulus through a predeterminedpath onto a conductor in a manner in which the ends of the annulus aremoved over the conductor, the distance between the ends of the annulusbeing less than the diameter of the conductor, and moving the ends ofthe annulus apart as they are moved over the conductor sufilciently toprevent contact between the conductor and at least the major portions ofthe ends of the annulus.

3. The method of feeding and applying insulating discs to conductors,which comprises moving toward and onto a conductor a washer-like, soft,plastic insulating disc having a slit therein extending from an outerperiphery of the disc to an inner periphery thereof, and graduallyexpanding the slit in the disc as it is moved toward and onto theconductor to restrict permanent deformation of the slit by the conductoras the disc is moved onto the conductor.

4. The method of feeding and applying insulating discs to conductors,which comprises moving transversely toward and onto a conductor aninsulating disc having a slit therein, the slit in the disc moving overthe conductor as the disc is moved onto the conductor, expanding theslit gradually as the disc is moved toward the conductor, and furtherexpanding the slit substantially without the aid of the conductor as thedisc is moved onto the conductor.

5. The method of feeding and applying insulating discs to conductors,which comprises moving an annular insulating disc facewise through apredetermined arcuate path toward a conductor positioned at the end ofthe path and tangent to the path, radially slitting the portion of theannular disc moving through the outer portion of the path as the disc ismoved toward the conductor, gradually wedging open the slit in the discas the disc is moved toward the conductor to an extent that the walls ofthe slit in the disc are held substantially out of contact with theconductor as the disc is moved to the end of the path.

6. In an apparatus for feeding and applying 10 insulating discs toconductors including an applicator wheel for moving an annular, plasticinsulatin disc through a predetermined path and for applying the disc toa conductor being advanced tangentially with respect to the ap- 1plicator wheel, a knife for slitting the disc radially at apredetermined point in the path of the disc and a thin arcuate guideadjacent to the lmife for entering the slit to keep it open and to guidethe disc, the improvement which com- 2 prises an expander positioned toenter the slit in the disc and extending from the guide substantially tothe conductor, said expander being tapered outwardly from the endthereof adjacent to the guide to the other end of the expander andserving to gradually open the slit in the disc as the disc is moved overthe expander, the portion of the expander near the conductor beingsuificiently thick to maintain the walls of the slit out of contact withthe conductor during at 30 least a portion of the movement of the discsover the conductor.

7. In an apparatus for feeding and applying annular, radially slit,plastic insulating discs to conductors including an applicator wheel formoving such a disc through a predetermined path and for applying thedisc to a conductor being advanced tangentially with respect to theapplicator wheel and a knife for slitting the disc, the improvementwhich comprises an expander extending arcuately along the outerperiphery of the applicator wheel from a point spaced from the conductorto the conductor, said expander being tapered from a thin end at thepoint Spaced from the conductor to a thicker end at the conjductor,whereby the slit in the insulating disc 5 is expanded as the disc ismoved along the ex- I predetermined point in the path of the disc and athin arcuate guide adjacent to the knife for 0 entering the slit toguide the disc and to hold open the slit therein, the improvement whichcomprises a wedge-shaped expander positioned enter the slit in the discand extending arcuately from the guide substantially to the 5 conductor,said expander being thin near the arcuate guide and being thicker nearthe conductor and serving to expand the slit in the disc to such anextent that the walls of the slit are kept substantially out of contactwith the conductor as the disc is applied to the conductor.

ALEXANDER C. FRANKWICH.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,669,053 Hamel May 8, 19282,045,087 Keller et a1 June 23, 1936 2,404,782 Berggrcn et a1 July 30,1946 2,426,623 Larsen Sept. 2, 1947

